[ILUG] Mirroring a filesystem across a network

[Brian O'Mahony]

We are using LVM already. However, the issue I see with this is I want to offload the actual tarring to backup system. Having never implemented DRDB, would it allow the following in some sort of script:

LVM snapshots the filesystem
DRDB service starts up. Mirrors the snapshot to the second server.
DRDB service shuts down
Second server mounts the snapshot, runs tar, and compresses everything.

Or have I misunderstood you?

I am currently looking at about 800Gb of data, and that is from the last two-three years. So I am expecting it to grow quite quickly. What ever method I end up using, I have to be able to scale for obvious reasons.

B

-----Original Message-----
From: ilug-bounces at linux.ie [mailto:ilug-bounces at linux.ie] On Behalf Of Brendan Minish
Sent: Thursday, February 10, 2011 4:25 PM
To: ilug at linux.ie
Subject: Re: [ILUG] Mirroring a filesystem across a network

One thing that you may wish to consider is using LVM (perhaps in combination with DRDB)

the big advantage with LVM is that you can snapshot the file system, make a consistent backup then delete the snapshot when done 


On Thu, 2011-02-10 at 16:17 +0000, Brian O'Mahony wrote:
> Im purchasing two new servers to replace our current Clearcase 
> infrastructure and was wondering has anyone got any suggestions on how 
> to do this. Here is a quick overview of what I need to do:
> 
> Primary server has a filesystem with active VOBs. These are open 
> files, and range from a few hundred megs to about 80GB.
> 
> I want the backup server to have a mirrored copy of this data (which 
> wouldn't be open, or active files), so there would be no need to lock 
> them (like we do in our current environment) so that these can be 
> tarred up, and then archived to tape. Or even possibly lock these on 
> the secondary server (may be needed if it is realtime sync), tarred 
> unlocked, and then updated.
> 
> Preferably I would like to have a realtime mirror. However this may 
> not be possible. I have done some reading on DRDB but from what I 
> surmise, the data is not accessible on the second server until the 
> primary goes offline.
> 
> The data will never need to be accessed from the secondary server with 
> the exception of tarring the files. If the primary goes down, this 
> data probably still wouldn't be used, as we would recover the data to 
> the previous night's backup, and then resync from a site replica, 
> which at worst would be out by 6 minutes.
> 
> We cannot use the site replica to backup, as to restore involves quite 
> a lot of changing the configuration on the site, as you are restoring 
> and would increase restore time dramatically.
> 
> I also thought about running an rsync, as the data doesn't nessisarily 
> need to be a mirror copy. While a mirror copy would be nice, an rsync 
> before the tarring of files would be enough. However im not sure of 
> the does and donts of using rsyn on open files, and also due to the 
> fact the largest files (70Gb) would probably have changed during its 
> own rsync.
> 
> Im wondering if anyone has any thoughts on this? Our will I have to 
> stay with our current method of locking the files on the Primary, 
> tarring, copying them to the backup and then off to archive.
> 
> Any suggestions are more than welcome.
> 
> Regards
> 
> B
> 
> 
> 
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